AM/ASK Envelope Detector in-output voltage relationship

Test circuit, the sensitivities of this test receiver unit is about -73dBm, a low gain configuration.

The signal generator specifying output power in dBm, in this way the raw data for input is in dBm

X-Axis converted to RMS voltage

Converted to mV for input, the plot is quite linear at first and later saturated after input raised to 1mV , corresponded to output voltage of 2.9V. The saturation is caused by the voltage supply of final opamp stage is limited to 7.4V battery voltage.

The linear range of the IF amp-detector circuit is about 25dB. AGC circuit must control the signal level fall within this range.